Semiconductor light emitting element, and its manufacturing method

• US 6,303,405 B1
• Filed: 09/24/1999
• Issued: 10/16/2001
• Est. Priority Date: 09/25/1998
• Status: Expired due to Term

• Current Assignee: Alpad Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nunoue, Shinya, Yoshida, Hiroaki, Itaya, Kazuhiko, Saito, Shinji, Nishio, Johji
• Primary Examiner(s): CHRISTIANSON, KEITH ALAN
• Application Number:
  US09/404,727
• Time in Patent Office: 753 Days
• Field of Search: 438/34, 438/46, 438/47, 438/455, 438/457, 438/458, 438/459, 438/479, 438/481, 438/795, 438/796, 438/977, 438/751, 117/952, 117/3, 257/13, 257/14, 257/15, 257/22, 372/44, 372/45
• US Class Current: 438/46
• CPC Class Codes: H01L 21/76251 using bonding techniques
• CPC Class Codes: H01L 2221/68318 Auxiliary support including means facilitating the separation of a device or wafer from the auxiliary support
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate

Abstract

A semiconductor light emitting element of nitride compound semiconductors excellent in cleavability, heat radiation and resistance to leakage is made by epitaxially grow a nitride compound semiconductor layers on a substrate of sapphire, for example, and thereafter separating the substrate. For separating the substrate, there are a technique using a abruption mechanism susceptible to a stress such as a “lift-off layer” and a recesses on a substrate. A technique using laser light to cause a local dense heat stress at the abruption mechanism is effective. A nitride compound semiconductor obtained by separating the substrate may be used as a new substrate to epitaxially grow high-quality nitride compound semiconductors thereon.

Claims

1. A method for manufacturing a semiconductor light emitting element, comprising the steps of:

forming on a single crystal substrate an abruption mechanism susceptible to a stress;

growing an epitaxial base layer of a nitride compound semiconductor on said abruption mechanism;

growing an epitaxial light emitting layer of a nitride compound semiconductor on said epitaxial base layer; and

separating said epitaxial base layer from said substrate by applying a stress to said abruption mechanism before or after said step of growing an epitaxial light emitting layer.

2. The method according to claim 1 wherein said abruption mechanism is a lift-off layer including at least either crystal defect or deficiencies.

3. The method according to claim 2 wherein said lift-off layer is an AlGaN layer including cracks or an InGaN layer including pits.

4. The method according to claim 3 wherein said step of separating said epitaxial base layer from said substrate includes a step of changing a temperature of said abruption mechanism.

5. The method according to claim 3 wherein said step of separating said epitaxial base layer from said substrate includes a step of applying an ultrasonic wave to said abruption mechanism.

6. The method according to claim 3 wherein said step of separating said epitaxial base layer from said substrate includes a step of irradiating said abruption mechanism with a laser light.

7. The method according to claim 3 wherein said substrate is made of sapphire.

8. The method according to claim 1 wherein said abruption mechanism is recesses of said substrate.

9. The method according to claim 8 wherein said step of forming said abruption mechanism includes a step of forming a seed layer of nitride compound semiconductor on said substrate, and said abruption mechanism is recesses of said substrate formed through said seed layer.

10. The method according to claim 8 wherein said recesses have a mask layer on their bottom in order to prevent growth of nitride compound semiconductor.

11. The method according to claim 8 wherein said step of separating said epitaxial base layer from said substrate includes a step of changing a temperature of said abruption mechanism.

12. The method according to claim 8 wherein said step of separating said epitaxial base layer from said substrate includes a step of applying an ultrasonic wave to said abruption mechanism.

13. The method according to claim 8 wherein said step of separating said epitaxial base layer from said substrate includes a step of irradiating said abruption mechanism with a laser light.

14. The method according to claim 8 wherein said substrate is made of sapphire.

17. The method of claim 3, wherein said separation of said epitaxial base layer from said substrate starts from said cracks or said pits.

18. The method of claim 3, wherein an Al composition of said AlGaN layer is in a range from 10% to 30%.

19. The method of claim 3, wherein an In composition of said InGaN layer is not less than 10%.

20. The method of claim 4, wherein said step of separating said epitaxial base layer from said substrate includes:

decreasing a temperature after growth of said epitaxial light emitting layer.

21. The method of claim 5, wherein said separation of said epitaxial base layer from said substrate starts from said cracks or said pits by applying said ultrasonic wave.

22. The method of claim 6, wherein said separation of said epitaxial base layer from said substrate starts from said cracks or said pits by irradiating with said laser light.

15. A semiconductor light emitting element fabricated by the steps of:

forming on a single crystal substrate an abruption mechanism susceptible to a stress;

growing an epitaxial base layer of a nitride compound semiconductor on said abruption mechanism;

growing an epitaxial light emitting layer of a nitride compound semiconductor on said epitaxial base layer; and

separating said epitaxial base layer from said substrate by applying a stress to said abruption mechanism before or after said step of growing an epitaxial light emitting layer.

16. A semiconductor light emitting element fabricated by the steps of:

forming on a single crystal substrate an abruption mechanism susceptible to a stress;

growing an epitaxial base layer of a nitride compound semiconductor on said abruption mechanism;

growing an epitaxial light emitting layer of a nitride compound semiconductor on said epitaxial base layer; and

separating said epitaxial base layer from said substrate by applying a stress to said abruption mechanism before or after said step of growing an epitaxial light emitting layer;

wherein;

said step of forming said abruption mechanism includes a step of forming a seed layer of nitride compound semiconductor on said substrate,

said abruption mechanism is recesses of said substrate formed through said seed layer, and

an electrode is formed onto a surface of said seed layer which was separated from said substrate by said step of separating said epitaxial base layer from said substrate.

23. A semiconductor light emitting element fabricated by:

forming on a single crystal substrate a lift-off layer susceptible to a stress, wherein said lift-off layer is an AlGaN layer including cracks or an InGaN layer including pits;

growing on an epitaxial base layer of a nitride compound semiconductor on said lift-off layer;

growing an epitaxial light emitting layer of a nitride compound semiconductor on said epitaxial base layer; and

separating said epitaxial base layer from said substrate by applying a stress to said lift-off layer before or after said step of growing an epitaxial light emitting layer.

24. The semiconductor light emitting element of claim 23, wherein said separation of said epitaxial base layer from said substrate starts from said cracks or said pits.

25. The semiconductor light emitting element of claim 23, wherein an Al composition of said AlGaN layer is in a range from 10% to 30%.

26. The semiconductor light emitting element of claim 23, wherein an In composition of said InGaN layer is not less than 10%.